Two men arrested in counter-terrorism raids in Sydney had armed themselves with a machete and a hunting knife and made a video detailing their plot, police say.
Authorities arrested the pair yesterday, the same day they were allegedly planning to maim or kill someone in a knife attack.
A home-made flag, representing the prescribed terrorist organisation Islamic State, was found at the men's Fairfield home, in Sydney's west, along with a machete, a hunting knife, and a video featuring one of the men making threats.
Deputy NSW Police Commissioner Catherine Burn said she did not know if the man planned to behead someone, and would not detail what was said in the video.
But she said the plot was "consistent with the IS messaging".
"We believe that the men were potentially going to harm somebody, maybe even kill somebody, and potentially using one of the items that we ... recovered yesterday - potentially a knife," she told reporters in Sydney.
It seems the men were arrested at the 11th hour.
Ms Burn said the men had planned to carry out their attack some time on Tuesday.
They were arrested just after 4pm that day at their Fairfield home.
Authorities say they don't know where the attack was to have been carried out.
But at this stage, there's nothing to link it to another plot that saw a number of people charged with terrorism-related offences after raids in Sydney and Brisbane in September.
Ms Burn said authorities had done an extraordinary job to prevent what she called an imminent terrorist attack, but would not say how the plot was uncovered.
But she did say the men were not previously on the radar of authorities.
The pair, aged 24 and 25, have been charged with acts done in preparation for, or planning terrorists acts. The are due to face court later on Wednesday.
Australian Federal Police Deputy Commissioner Michael Phelan said authorities were facing a new landscape when it came to protecting the public.
He moved to reassure Australians that police and intelligence agencies are up to the challenge.
"The attack was imminent yesterday, and we acted as early as we possibly could," he told reporters.
Ms Burn said agencies were facing a very challenging situation.
"There are a small group of people, they may not be known to police, who develop an intent to carry out an attack," she said.
What was in the favour of police was that they weren't necessarily pursuing sophisticated methods, she said.
The raids, codenamed Operation CASTRUM, were carried out as by NSW Police's Joint Counter Terrorism Team, police said on Wednesday.
The men, who are due to appear in Fairfield Local Court on Wednesday, have been charged with Acts done in preparation for, or planning terrorists acts.
Police allege the two men were going to undertake an act of terrorism in Australia as revenge for incidents overseas.
Searches were also conducted at the residence, as well as a motor vehicle, and where the men work.
